1. Field of the Invention
This invention relates to overbasing of magnesium compounds which may be utilized in lubricants and rust preventive compositions
2. Description of the Art
It is known from U.S. Pat. No. 3,629,109 issued Dec. 21, 1971 to Gergel, Karn and King that lower alkanols may be utilized as copromoters with water to overbase a substrate with a source of magnesium. Asseff et al in U.S. Pat. No. 2,616,911 issued Nov. 4, 1952 describes a process for overbasing an alkaline earth material in the presence of an alkylphenol. In particular, Asseff discloses the use of para-tertiarybutyl phenol. Under the conditions of Asseff, it is disclosed that the water present (from the neutralization during overbasing and any added water) is substantially removed during the overbasing operations.
U.S. Pat. No. 2,695,910 issued Nov. 30, 1954 to Asseff et al describes the production of superbased salts prepared by treating an organic salt complex with a material which possesses acid characteristics under the process conditions, and then combining the treated organic salt complex with an inorganic metal compound with or without water and with or without a promoter present and then substantially removing any remaining water. Among the promoters of Asseff which are stated to be possible materials which may be included during processing are phenol and various alkylated phenols.
Asseff et al in U.S. Pat. No. 2,626,294 issued Nov. 4, 1982 discusses a method of obtaining a higher metal ratio when overbasing alkaline earth materials. The examples of this Asseff patent describe being overbased to a metal ratio of less than 6. As defined, the metal ratio is the ratio of the number of equivalents of the metal to the number of equivalents of the substrate. This Asseff patent states that phenolic compounds may be utilized and defines such materials as being organic compounds having a hydroxy group directly attached to the carbon atom of a benzenoid ring.
Schlicht in U.S. Pat. No. 2,856,359 issued Oct. 14, 1958 describes the production of oil-soluble superbasic sulfonates of alkaline earth metal salts. Schlicht describes promoters for the overbasing reaction including aromatic carboxylic acids, lower molecular weight sulfonic acids, cresols, xylenols, catechols or 3,242,080 issued Mar. 22, 1966 describes hyperbasic sulfonate compositions of alkaline earth metals. Wiley describes the use of polar organic materials such as saturated aliphatic hydrocarbon alcohols containing from one to five hydroxy groups, alkanones, fatty acids, primary alkyl amines, aryl substituted and alkaryl substituted alkanols, phenol, alkylated phenols, saccharides, carbohydrates, animal and vegetable fats and oils as being useful in overbasing operations.
McMillen in U.S. Pat. No. 3,242,079 issued Mar. 22, 1966 describes obtaining homogeneous grease compositions characterized by high basicity. The compositions of McMillen are also stated to be useful in lubricants, additives for lubricants, asphalts, fuels, coating oils, caulking compositions and the like. McMillen states that he obtains a fluid mineral oil solution which contains from about 10 to about 70% of a carbonated, basically alkaline earth metal salt of an acid having at least 12 aliphatic carbon atoms and which is either a sulfonic acid or a carboxylic acid through the use of a lower aliphatic carboxylic acid, water, or a water-alcohol mixture at conditions between 25.degree. C. and the reflux temperature of the mixture.
U.S. Pat. No. 3,372,114 issued Mar. 5, 1968 to Rense describes the production of gelled materials useful as lubricant additives in greases prepared by contacting a fluid mineral oil solution of a carbonated, basic complex of an alkaline earth metal and an organic carboxylic or sulfonic acid, salt thereof, or carboxylic ester containing at least 12 aliphatic carbon atoms. Rense further states that his complex is characterized by having a metal ratio of at least 4.5 and that an essential step in the processing is contacting the aforementioned mixture with oxygen at a temperature of about 150.degree. C. to about 300.degree. C.
McMillen in U.S. Pat. No. 3,377,283 describes a continuous operation for obtaining an alkali or alkaline earth metal overbased organic material by effecting the conversion in an elongated heating tube at from 90.degree. C. to 320.degree. C. Water, carboxylic acids and alcohols are stated to be suitable conversion agents by McMillen.
Scher in U.S. Pat. No. 3,422,013 issued Jan. 14, 1969 describes a process for the preparation of non-Newtonian colloidal dispersed systems obtained by the treatment of carbonated, highly basic calcium sulfonate with water. Various alcohols or phenols, mercaptans, amines or acid-nitro compounds, metal phenates or enolic compounds may be utilized to promote the overbasing reactions.
Corringer U.S. Pat. No. 3,671,430 discloses using alkylphenols or alkylphenol sulfides in an overbasing process. The Corringer patent which issued June 20, 1972 specifically discloses calcium hydroxide as the source of the alkaline earth metal. Siga et al in U.S. Pat. No. 4,057,504 issued Nov. 8, 1977 discusses the use of dihydric alcohols, phenols and elemental sulfur in obtaining an overbased compound. U.S. Pat. No.2,761,845 issued Sept. 4, 1956 to Rogers et al describes the use of phenol sulfides in lubricant compositions.
It has been observed in the present invention that the later described method for overbasing magnesium compounds provides superior results in performance and in end use compositions.
Throughout the specification and claims percentages and ratios are by weight, temperatures are Celsius and pressures are in KPa gauge unless otherwise indicated. All ranges used herein are exemplary and may be combined. To the extent that any of the references cited in this application are pertinent to the present invention, they are herein incorporated by reference.